Component Tester

Description

A DIY, Arduino-based component tester for transistors, resistors, capacitors and more!

Look, I know you can buy component testers, and I know some of them are coming in a reasonable prices these days. But that doesn’t always matter to some of us.

Some of us like to get hands-on and love the feeling of building something for ourselves. This project is one of those – it’s fun to put together, infinitely useful, and something you can tweak, edit and build on in the future.

Featuring…

Multiple connectors to test components:

• 2x 8 pin connectors in varying 1-2-3 pin combinations
• 3 pin terminal block for testing large components
• 2 pad SMD tester for surface mount resistors and capacitors
• 3 pad SMD tester for surface mount transistors

Large 16×2 character, LCD backlit screen with clear values and pin identifiers.

12mm tactile push button to reset and re-test.

Powered by USB through the onboard Arduino USB socket.

What you’ll get…

A lot of the parts needed for this project are easy to get hold of, or if you regularly build pedals you’ll likely have. However, a few bits were slightly harder to find so they’ll be included in your purchase. When you order this PCB, we’ll also send you:

• 1x Black project PCB
• 1x Pre-loaded Arduino Nano ready to be fitted – no software editing or uploading required
• 1x 3 pin terminal block – for testing larger components
• 1x 12mm push button
• 1x LCD 16×2 screen
• 1x Right-angle connector for the LCD screen

Component list

Part #	Value	Component
R1	680r	Metal film resistor
R3	680r	Metal film resistor
R5	680r	Metal film resistor
R2	470k	Metal film resistor
R4	470k	Metal film resistor
R6	470k	Metal film resistor
R7	22k	Metal film resistor
2x 15-way single row socket		Arduino connections
1x 8+8 double row socket		Component pin sockets
4x	6mm	Nylon PCB spacers
8x	M3 6mm	Nylon screws

This project takes inspiration (and source code) from this build by Creative Techos.

Build guide

The resistors are all used to help the Arduino define some base values which then drive the accuracy of the tester. Because of this, I’d advise metal film resistors as they tend to have improved tolerances and you might want to grab a batch and measure them with a multimeter to find those that measure as close to the required values as possible.

Step 1 – add the resistors.

Step 2 – add the LCD screen. Fit the right-angle connector to the LCD pins and line it up but don’t solder it yet. Fix it in place using the spacers between the LCD and the PCB and the M3 screws. Once fixed, solder the connector from the rear of the PCB.

Step 3 –  add the button.

Step 4 – add the pin connectors, just making sure they’re as straight as possible.

Step 5 – add the Arduino – go careful but it should line up perfectly and slide into the connectors easily. Push firmly to click it into place.

Step 6 – power up with a USB cable and give it a quick test. Everything should power up straight away and you’ll get a loader message on the LCD screen. Pressing the button will give you an error that there’s a missing (or broken) component. Give it a test with some components you know the values of – resistors are good – and validate the results.

Step 7 – optionally run a calibration. Using wires or trimmed component legs, connect test sockets 1, 2 and 3 together and press to test. The device will detect that all 3 sockets are shorted and will run a diagnostic and calibration test. Once complete, you should experience more accuracy in readings.

Example readings

In addition to these examples, you can also test MosFETS, thyristors, and inductors.

PNP Germanium transistor

A

The tester confirms this transistor as PNP and identifies pin 1 as the *, pin 2 as the *, and pin 3 as the *. The hFE reads at ~888.

NPN Silicon transistor

A

The tester confirms this transistor as NPN and identifies pin 1 as the *, pin 2 as the *, and pin 3 as the *. The hFE reads at ~888.

Capacitors

A

The tester confirms this component is a capacitor, connected between pins 1 and 3, with a value of 888nF.

B

The tester confirms this as an electrolytic capacitor, connected between pins 1 and 2, with a value of 888uF.

Resistors

A

The tester confirms this as a resistor measuring 888 ohms, connected between pins 1 and 3.

B

The tester confirms this as a resistor measuring 888 ohms, connected between pins 2 and 3.

LEDs

A

The tester confirms this as a diode, connected between pins 1 and 2 (1 being the Anode+ and 2 being the Cathode-) and a forward voltage of 8v.

Diodes

A

The tester confirms this as a diode, connected between pins 1 and 3 (1 being the Cathode- and 3 being the Anode-) and a forward voltage of 8v.